This article describes an application of the lFP energy production and transformation model. The present mode-ing study specifically aims to use dynamic linear programming to analyze the optimum production conditions for the French refining and basic petrochemical sectors. On the basis of product supply and demand scenarios, this study attempts to describe optimum investments for these two sectors for the next two decades. Special assumptions concerning the dieselization of road vehicles and the inclusion of oxygenated hydrocarbons in automotive fuels have been formulated along with contrasting trends in the consumption of basic petrochemical products. The article concludes with a brief parameterization study giving a static approach to the influence that a propylene/ethylene substitution might have, at the level of the demand, on the production facilities of both sectors.